I'm having trouble figuring out how to wire these Polk audio MM691's.
I have 2 pair and the idea is to series them to a wet sounds sd4.
They are 2.7ohm, and for everything to work correctly. They need to be in series.

The other 2 channels of the amp will have 2 pair of xs650 in parallel at 2 ohm.

So 2chan will see 2ohm.
2chan at 5.4ohm.
The guys at wet sounds said it would work, but I can't figure out how to wire the polks with the crossovers. Or do I even need the cross overs.
Please help me!

J M,
You must maintain the passive crossovers.
In a standard series wiring, the amplifier + goes to the first speaker's +, the first speaker - goes to the second speaker +, and the second speaker - goes to the amplifier -.
Now you may be getting confused by the crossover module, but nothing changes. Connect the passive crossover to the speaker terminals as normal. Treat the crossover +/- inputs as the only terminals when you do your series wiring. In other words, simply replace the crossover inputs with what would normally be the speaker terminals.
So the amplifier + goes to the first speaker crossover input +, the first speaker crossover input - goes to the second speaker crossover input +, and the second speaker crossover input - goes to the amplifier -.

nothing about the wiring AT the cross-over will differ from a parallel wire install or wiring a single speaker. Your series configuration will take place with the speaker leads between the amp and the cross-over. it will be wired in series just like any other speaker or sub-woofer.

Well today was a hell of a day.
On the way to the river for the day, something in the road punctured and ruined a brand new trailer tire.
The damage was not repairable, ended up having to replace the tire.

While inside the tire shop for the bit of 5mins I was inside. I believe someone decided to walk off with the box of those MM's that were on the rear seat of the boat.
Problem is, there was only one of them in the box.

So since some bastard in Sacramento has 1 MM, and I have the other.
Think I can buy 1 somewhere? Lol